friends:
Armbrust or DIY is probably best bet for a snapshot. I'll lay money on the fact that the folks at Federal DO NOT KNOW, from lot to lot, the pressures of their loads, EXCEPT for the fact that it has passed the SAAMI pressure standards using the SAAMI statistical methodology.
As the powder changes from lot to lot, both in chemical makeup and in the amount necessary to acheive the velocity they seek, I can see why they are unwilling to say "ZZZ shell runs 95xx psi".
Also, remember, any info you get from a one-time test will be reasonably valid only for that lot of shells. Get another lot, change any component, and the info ceases to be really useful but becomes historical data.
Regards
GKT
